Rewired fuel pump, now pressure is out of control

[MyBeatGSX]

Well just like the title says, I rewired my pump last weekend. Thankfully it got rid of my low fuel pressure when hot problem that I posted about a month ago. The new problem is that I now can't get fuel pressure below 41psi. Before the rewire I had 40psi base pressure with ~35psi under vacuum (it wasn't very consistant). I now have 45psi base and 41psi under vacuum (be that 18in/hg or 25in/hg, it never goes lower). I cannot adjust lower than 41psi, it just doesn't want to go that low. If I pinch the vacuum referance line and then let go, fuel pressure will spike down to 38psi where it should be, but then very quickly climbs back up to 41psi.

I have no idea what the problem could be. I have a 255HP with an Aeromotive AFPR, all fuel lines are stock. I think about 90123478209759842308523 other DSMers are running this setup without a problem.

 

[steve]

Put a hose on the return port and run it to a big gas can. If the FPR starts behaving you might have the 2G return line restriction.

Steve

 

[larsrya8]

Try the bucket suggestion first. If it doesn't, that means that there is something wrong with the AFPR. Check to see there isn't anything restricting the movement of the spring (like the pressure source fitting).

 

[MyBeatGSX]

One more thing to do this weekend.

So what is the 2G return line restriction?

 

[steve]

It's not something I have personal experence with but from what I remember there is a problem with how the return line ends in the 2G fuel tank that causes a restriction in the flow rate. If I have time I'll see if I can find the source that I picked the information up from.

Let us know how the "bucket" test goes.

Steve